France Première STI2D (industrial sciences and sustainable development) — 1re specialties

Chapters: 10

1. 1. Product design principles and sustainable development

The project approach · Systems engineering tools · Product competitiveness · Creativity and technological innovation · Environmental approach

Project Management – A project is a one-time piece of work with a clear goal, a start and an end. Project management means planning and controlling it so it meets its scope on time and within cost. The life cycle runs initiate, plan, execute, monitor and close. Planners break the work into tasks (WBS), place them on a Gantt chart, find the critical path, manage risks and review lessons learned at the end.
Systems Engineering – Systems engineering designs a product as a whole system. It starts from the user's need, turns it into measurable requirements, follows the flows of matter, energy and information through the parts, and checks the result on the way back up the V-cycle: verify (built right?) and validate (right thing?).
Product Competitiveness: Innovation, Patents, Ergonomics and Trade-offs – A product is competitive when customers find it gives more value for its price than other choices. Companies raise competitiveness by innovating (product, process, marketing), protecting ideas (patents, standards, industrial property), designing for people (ergonomics), balancing function against cost and need, and keeping environmental impact low.
The Design Process: From Problem to Product – The design process is a loop of steps designers use to solve a real problem for real people: investigate the need, define it in a brief and a measurable specification, generate many ideas, build a prototype, then test and evaluate it against the specification. Whatever fails sends you back round the loop. This repeating is called iteration, and it is how almost every product, app, building and artwork is improved.
Sustainable Design: Products That Are Kind to People and Planet – Sustainable design means making products that meet our needs while harming nature and people as little as possible. Every product has a life cycle: materials, making, transport, use and end of life. A life cycle assessment adds up the ecological footprint (energy, CO₂, water, waste) at each stage. The social footprint is the effect on workers and communities: pay, safety, child labour, fair trade. Designers use the six Rs (rethink, refuse, reduce, reuse, repair, recycle), design for maintenance, repair and disassembly, and avoid planned obsolescence. Ecodesign also weighs the economic side: a product must be affordable and profitable, so the best designs balance environment, society and economy.

2. 2. Functional and structural analysis of products

Matter, energy and information flows · Frames and envelopes · Power chains · Information chain

Systems Engineering – Systems engineering designs a product as a whole system. It starts from the user's need, turns it into measurable requirements, follows the flows of matter, energy and information through the parts, and checks the result on the way back up the V-cycle: verify (built right?) and validate (right thing?).
Civil Engineering: How Buildings Stand Up and Keep the Weather Out – Civil engineers design and build structures such as houses, bridges, roads and dams. A building has a frame (columns, beams, slabs, bracing) that carries loads down to the foundation and soil, and an envelope (walls, curtain walls, roof) that protects people inside. Engineers choose materials (wood, steel, concrete), check forces and plan for the site and the environment.
Conservation of Energy – Energy cannot be created or destroyed. It only changes from one form to another, or moves from one object to another. The total energy of a closed system stays the same. When there is no friction, mechanical energy (potential + kinetic) stays constant: mgh + ½mv² = constant. With friction, some mechanical energy turns into heat (thermal energy), but the total is still the same. Efficiency = useful energy out ÷ total energy in × 100%.
Information Systems – An information system (IS) is a set of people, hardware, software, data, networks and procedures that work together to collect, store, process and share information. It turns raw data into useful information through a chain: capture, encode, send, store, process and present. Systems are built in a cycle (plan, analyse, design, build, test, run and improve). They make work faster and let many people share knowledge, but they cost money, can fail, can be hacked and can make an organisation rigid.

3. 3. Behaviour of products

Modelling and simulation · Mechanical behaviour · Energy behaviour · Information behaviour

Modelling and Simulation in Engineering – Engineers test a design on a model before making it. A model can be physical (a scale model or prototype), mathematical (equations) or digital (a CAD model). Every model has effort variables (force, voltage, pressure) and flow variables (speed, current, flow rate); effort × flow = power. Simulation software cuts a part into small finite elements, writes equations for each and a solver finds the answer; moving systems are solved in small time steps. Results such as stress, bending and safety factor are read from colour maps and graphs. A finer mesh or smaller time step is more accurate but takes more computing time. Finally, results are checked against real tests with sensors, taking measurement errors into account.
Torque, Angular Momentum and Equilibrium of Rigid Bodies – Torque is the turning effect of a force: τ = r × F, size rF sinθ, unit N m. Angular momentum is the turning version of momentum: L = r × p; for a body spinning about a fixed axis L = Iω. Torque changes angular momentum: τ = dL/dt. If the outside torque is zero, L stays constant, so pulling mass in makes a body spin faster. A rigid body is in equilibrium when the total force is zero (no sliding) and the total torque about any point is zero (no turning).
Work, Energy and Power – Work is done when a force moves an object: W = F × s, measured in joules (J). Energy is the ability to do work. A moving body has kinetic energy ½mv²; a raised body has potential energy mgh. Energy is never made or destroyed, only changed from one form to another. Power is how fast work is done: P = W ÷ t, in watts. Simple machines like levers and pulleys let a small effort move a big load.
Computer Networks and How the Internet Works – A network is a group of devices linked to share data. Each device has an IP address. Data is cut into numbered packets. Routers pass each packet hop by hop towards its address, and TCP puts the packets back in order. DNS turns a website name into an IP address. Clients ask, servers answer. Firewalls, passwords, updates and encryption keep a network safe.
How Networks Grew and How Data Travels – A computer network is a group of connected devices that share data. Networking began with ARPANET (1969), grew into NSFNET (1980s) for universities, and joined with other networks to become the Internet, a network of networks. Every data communication has five parts: sender, receiver, message, communication media and protocol. Bandwidth is the range of frequencies a channel can carry (in Hz); data rate is how many bits travel per second (bps). Every device on a network has an IP address. Data can move by circuit switching (a fixed path is booked first) or packet switching (data is cut into packets that travel on their own).

4. 4. Eco-design of products

Tools to represent reality · Design approaches · Product design

CAD Modelling: From a Sketch to a 3D Part – CAD (computer-aided design) means using a computer to draw and build exact models of objects before they are made. A design starts as a freehand sketch. In CAD it becomes a 2D sketch with constraints and dimensions. 3D tools such as extrude, revolve and cut turn the sketch into a solid. Each step is saved in a feature tree, so changing one size rebuilds the whole model. Parts are joined in assemblies, tested by simulation, shared as drawings and sent to 3D printers, laser cutters or CNC machines.
Material Selection and Eco-design – Choosing a material means matching what the product needs with what each material can do. First list the needs (strength, weight, cost, looks, safety, the planet). Then give each candidate a score for each need, add weights for what matters most, and compare totals. Eco-design adds the whole life of the product: raw material, making, use, and end of life. Natural materials come from living things or the ground; artificial materials are made by people in factories. The same careful method also works for choosing software, a processor or an interface.
The Design Process: From Problem to Product – The design process is a loop of steps designers use to solve a real problem for real people: investigate the need, define it in a brief and a measurable specification, generate many ideas, build a prototype, then test and evaluate it against the specification. Whatever fails sends you back round the loop. This repeating is called iteration, and it is how almost every product, app, building and artwork is improved.

5. 5. Construction solutions

Frame and envelope components · Power components · Information components

Civil Engineering: How Buildings Stand Up and Keep the Weather Out – Civil engineers design and build structures such as houses, bridges, roads and dams. A building has a frame (columns, beams, slabs, bracing) that carries loads down to the foundation and soil, and an envelope (walls, curtain walls, roof) that protects people inside. Engineers choose materials (wood, steel, concrete), check forces and plan for the site and the environment.
Energy Storage: Keeping Energy for Later – Energy from the sun or wind is not always there when we need it. A store keeps energy for later. Mechanical stores keep it in height, springs or spinning wheels (E = mgh for a raised weight). Chemical stores keep it in fuels and batteries (energy in watt-hours = volts × amp-hours). Thermal stores keep it as heat in hot water or hot material (Q = m × c × ΔT). Around the store sit the power parts: converters, modulators and adapters change the form of the electricity; gearboxes, belts and couplings pass motion on; bearings and slides guide moving parts; seals keep fluids in and dirt out. No store gives back everything that goes in, so efficiency is below 100%.
Physical Computing: Making Code Sense and Move – Physical computing joins code to the real world. Sensors measure something (light, temperature, distance, button presses) and turn it into a number. A microcontroller runs a program that decides what to do with that number. Actuators (LEDs, buzzers, motors, screens) act on the world. This input–process–output cycle runs again and again in a loop. Using thresholds, conditions and feedback, we build night lights, smart plant waterers, wearables and interactive art.

6. 6. Prototyping and experiments

Rapid prototyping · Experiments and tests · Verifying and validating the prototype

Prototyping: Make It, Test It, Make It Better – A prototype is an early, testable version of a product or idea. Low-fidelity prototypes (sketches, paper, cardboard) are fast and cheap and test the idea; high-fidelity prototypes (3D prints, working models) look and work like the real thing. Rapid prototyping uses machines such as 3D printers (additive: build layer by layer), laser cutters and CNC mills (subtractive: cut material away). Each prototype is tested with a clear goal and fair method, results are recorded, and the design is improved in a loop: build, test, learn, improve. Finally the project is documented and presented.
Systems Engineering – Systems engineering designs a product as a whole system. It starts from the user's need, turns it into measurable requirements, follows the flows of matter, energy and information through the parts, and checks the result on the way back up the V-cycle: verify (built right?) and validate (right thing?).

7. Physics-chemistry: Energy

Energy and its challenges · Chemical energy · Electrical energy · Internal energy · Mechanical energy · Energy carried by light

Work, Energy and Power – Work is done when a force moves an object: W = F × s, measured in joules (J). Energy is the ability to do work. A moving body has kinetic energy ½mv²; a raised body has potential energy mgh. Energy is never made or destroyed, only changed from one form to another. Power is how fast work is done: P = W ÷ t, in watts. Simple machines like levers and pulleys let a small effort move a big load.
Combustion – Combustion (burning) is a chemical change in which a fuel reacts fast with oxygen and gives out heat and light. It needs three things: fuel, oxygen and heat (to reach the ignition temperature). Remove any one and the fire goes out. With plenty of air, fuels that contain carbon and hydrogen burn completely to carbon dioxide and water (blue flame). With too little air, burning is incomplete and gives soot and poisonous carbon monoxide (yellow, smoky flame). Carbon dioxide turns limewater milky. The energy released by burning 1 g of a fuel is its calorific value.
Electric Current, Potential Difference and Electric Circuits – Electric current is the rate of flow of charge, I = Q/t, measured in amperes with an ammeter joined in series. Potential difference is the work done to move a unit charge between two points, V = W/Q, measured in volts with a voltmeter joined in parallel. Charge flows only in a closed circuit.
Heat Transfer: Conduction, Convection and Radiation – Heat moves in three ways. In conduction, heat passes from particle to particle while the particles stay in place; the rate through a slab is H = kA(T₁ − T₂)/L, where k is thermal conductivity. In convection, the fluid itself moves: hot fluid is lighter and rises, cool fluid sinks. In radiation, heat travels as electromagnetic waves and needs no medium. A blackbody absorbs all radiation and is the best emitter. Its peak wavelength falls as temperature rises (Wien: λmT = b), and its total emitted power grows as T⁴ (Stefan: P = σAT⁴). Newton's law of cooling says a body cools at a rate proportional to its temperature excess over the surroundings.
Motion: Distance, Speed, Velocity, Acceleration and Graphs – An object is in motion when its position changes with time. Distance is the full path length (a scalar); displacement is the straight gap from start to finish with a direction (a vector). Speed = distance ÷ time; velocity = displacement ÷ time. Acceleration = change in velocity ÷ time. The slope of an s–t graph gives velocity, the slope of a v–t graph gives acceleration, and the area under a v–t graph gives the distance. For uniform acceleration: v = u + at, s = ut + ½at², v² = u² + 2as.
Light and Colour: Mixing, Seeing and Energy of Light – White light is a mix of colours (red to violet). Lights add: red + green + blue make white (additive mixing, used by screens). Paints take away: cyan + magenta + yellow make near-black (subtractive mixing). An object has a colour because it reflects some colours and absorbs the rest. Eyes use three kinds of cone cells. Light colour tells its energy: E = hf, blue photons carry more energy than red.

8. Physics-chemistry: Matter and materials

Material properties and structure of matter · Combustions · Redox, corrosion and cells

Materials and Their Properties: Why Things Are Made of What They Are – Every product is made from materials chosen for their properties. The main families are papers and boards, timbers, metals, polymers (plastics) and textiles. Physical properties describe what a material is like (density, conductivity, how it reacts to heat and water). Working properties describe how it behaves when we use or shape it (strength, hardness, toughness, elasticity, plasticity, malleability, ductility). Materials come from natural sources such as trees, ores and crude oil, and are sold in standard stock forms like sheets, bars, tubes and planks. A designer picks a material by matching its properties to the job, and also thinks about cost, availability, looks and the environment.
Combustion – Combustion (burning) is a chemical change in which a fuel reacts fast with oxygen and gives out heat and light. It needs three things: fuel, oxygen and heat (to reach the ignition temperature). Remove any one and the fire goes out. With plenty of air, fuels that contain carbon and hydrogen burn completely to carbon dioxide and water (blue flame). With too little air, burning is incomplete and gives soot and poisonous carbon monoxide (yellow, smoky flame). Carbon dioxide turns limewater milky. The energy released by burning 1 g of a fuel is its calorific value.
Redox Reactions: From Oxygen to Electron Transfer – Oxidation first meant adding oxygen or removing hydrogen. Reduction meant the opposite. Today we use a bigger idea: oxidation is losing electrons and reduction is gaining electrons. Both always happen together, so we call them redox reactions. A more active metal gives electrons to the ion of a less active metal.

9. Physics-chemistry: Waves and information

What is a wave · Sound waves · Electromagnetic waves

Sound – Sound is made by vibrating objects. It travels through a medium (air, water, solids) as a longitudinal wave: particles move back and forth, making crowded parts (compressions) and spread-out parts (rarefactions). Frequency (Hz) sets the pitch, amplitude sets the loudness, and speed v = f × λ. Sound cannot travel in vacuum. Humans hear 20 Hz to 20,000 Hz; below is infrasound, above is ultrasound. Reflected sound gives echoes, used and controlled in buildings.
Electromagnetic Waves – A changing electric field acts like a current, called the displacement current, and it makes a magnetic field. A changing magnetic field makes an electric field. Together they travel as an electromagnetic (EM) wave at c = 3 × 10⁸ m/s, even through empty space. E and B are at right angles to each other and to the direction of travel, so EM waves are transverse. Sorted by wavelength, they form the spectrum: radio, microwave, infrared, visible, ultraviolet, X-rays and gamma rays.

10. Mathematics

Trigonometry · Dot product · Complex numbers · Derivatives · Antiderivatives

Trigonometric Functions: Radians, Unit Circle, Graphs and Identities – An angle of one radian cuts an arc equal to the radius, so π radians = 180°. On a unit circle, the point at angle x is P = (cos x, sin x), which gives sin²x + cos²x = 1 and extends sine and cosine to every real number. The signs follow 'All, Sin, Tan, Cos' in quadrants I to IV; sin x and cos x repeat every 2π and stay between −1 and 1. Compound-angle formulas such as cos(A + B) = cos A cos B − sin A sin B lead to tan(A + B), cot(A + B), sum-to-product, double-angle and triple-angle identities.
Vector Algebra – A vector has a size (magnitude) and a direction. In 3D we write it as a = xî + yĵ + zk̂. Its length is |a| = √(x² + y² + z²). Its direction cosines are l = x/|a|, m = y/|a|, n = z/|a|, and l² + m² + n² = 1. Vectors are added head-to-tail (triangle law) or component by component. ka stretches a by k and flips it if k is negative. The point dividing AB in m : n has position vector (mb + na)/(m + n) inside and (mb − na)/(m − n) outside. Dot product a·b = |a||b|cosθ gives a number and tells the angle and the projection. Cross product a×b = |a||b|sinθ n̂ gives a vector at right angles to both; its length is the area of the parallelogram on a and b.
Complex Numbers and Quadratic Equations – Some equations like x² + 1 = 0 have no real answer, because no real number has a negative square. So we add a new number i with i² = −1. A complex number is z = a + ib: a is the real part and b is the imaginary part. We add, subtract and multiply complex numbers like algebra, and replace i² by −1. To divide, we multiply top and bottom by the conjugate. On the Argand plane, z = a + ib is the point (a, b). The conjugate a − ib is its mirror image in the real axis, and the modulus √(a² + b²) is its distance from the origin. Every quadratic ax² + bx + c = 0 with D = b² − 4ac < 0 has two complex roots that are conjugates of each other.
Continuity and Differentiability – A function is continuous at a point when its graph has no break there: the left limit, the right limit and the value are all equal. The derivative is the slope of the tangent line. With the chain rule, implicit differentiation, the rules for eˣ, ln x and inverse trig functions, logarithmic differentiation and parametric forms, you can differentiate almost any Class 12 function. The second derivative tells how the slope itself changes, that is, how the curve bends.
Integrals – Integration undoes differentiation: if F′(x) = f(x), then ∫f(x) dx = F(x) + C. We integrate with standard formulas, substitution (replace an inside part by u), partial fractions (split a fraction) and by parts (∫u dv = uv − ∫v du). A definite integral ∫ₐᵇ f(x) dx is the signed area under the curve from a to b, and the fundamental theorem says it equals F(b) − F(a). Its properties make many hard integrals easy.